1. Field of Invention
The present invention relates to shredders for destroying articles, such as documents, CDs, etc.
2. Description of Related Art
Shredders are well known devices for destroying substrate articles, such as documents, CDs, floppy disks, etc. Typically, users purchase shredders to destroy sensitive articles, such as credit card statements with account information, documents containing company trade secrets, etc.
A common type of shredder has a shredder mechanism contained within a housing that is removably mounted atop a container. The shredder mechanism typically has a series of cutter elements that shred articles fed therein and discharge the shredded articles downwardly into the container. The shredder typically has a stated capacity, such as a number of sheets of paper (typically of 20 lb. weight) that may be shredded at one time; however, the feed throat of a typical shredder can receive more sheets of paper than the stated capacity. A common frustration of users of shredders includes feeding too many papers into the feed throat, only to have the shredder jam after it has started to shred the papers. To free the shredder of the papers, the user typically reverses the direction of rotation of the cutter elements via a switch until the papers become free. Occasionally, the jam may be so severe that reversing may not free the paper entirely, and the paper must be pulled out manually, which may be difficult with the paper bound between blades of the cutter elements.
The assignee of this application, Fellowes, Inc., has developed thickness sensing technologies for shredders. By sensing thickness of paper or articles being fed into the shredder, the shredder can be stopped (or not started) before a severe jam occurs. U.S. Patent Application Publication Nos. 2006/0054725 A1 (U.S. Pat. No. 7,661,614) , 2006/0219827 A1 (U.S. Pat. No. 7,631,822), 2009/0090797 A1, and 2007/00221767 A1 disclose, among other things, a detector that can determine if an overly thick object is being inserted in a shredder throat. See also, U.S. patent application Ser. Nos. 12/579,905, 12/409,896, 12/466,775, and 12/487,220, also owned by Fellowes, Inc. Other examples of known shredders with thickness sensing features designed to prevent the cutter elements from jamming are U.S. Patent Application Publication Nos. 2009/0025239 A1 (U.S. Pat. No. 7,584,545), 2007/0246582 A2 (U.S. Pat. No. 7,624,938), and 2009/0032629 A1.
No admission is made as to whether the foregoing thickness sensing technologies constitute prior art.